Lightweight, compactly deployable support structure with telescoping members

ABSTRACT

A compactly stowable and deployable support architecture, such as may be used for supporting an energy directing surface, includes radial and hoop support members including upwardly and downwardly extending strut members for deploying a surface, such as a mesh-configured antenna reflector. In one aspect, at least one strut is formed as a telescoping tube member. A multi-sided foldable hoop structure has a plurality of foldable joints, and generally radial struts that extend from and are foldable about corner joints of the hoop structure. At least one drive mechanism is coupled to torque tubes that drive geared hinges of the multi-sided hoop structure. The hinges and drive linkages are geared to synchronously unfold the multi-sided foldable hoop structure and the radial struts, so that the antenna surface may be smoothly deployed from its stowed condition.

RELATED APPLICATION

[0001] This application is a continuation-in-part application based uponprior filed copending application Ser. No. 09/330,959, filed Jun. 11,1999.

FIELD OF THE INVENTION

[0002] The present invention relates to support structures, such as butnot limited to those for deploying energy directing surfaces (e.g.,reflectors), in either terrestrial or space applications, and isparticularly directed to a new and improved compactly stowable supportarchitecture, having both radial and circumferential structuralelements, that are configured to be compactly foldable, and to becontrollably driven so as deploy an unfurlable medium, such as amesh-configured reflector.

BACKGROUND OF THE INVENTION

[0003] The use of large reflector structures for satellite communicationnetworks is becoming more widespread as demand for mobile communicationsincreases. As the required aperture size or number of reflectors perspace-deployed communication site increases, the availability oflightweight, compactly packaged antenna structures is a key element incontinuing industry growth.

[0004] A non-limiting example of an umbrella type and folded rib meshreflector that has been deployed by the National Aeronautics and SpaceAdministration (NASA) for over a quarter of century is the Tracking DataRelay System (TDRS) reflector antenna system. In its deployed state, themetallic mesh reflector structure of the TDRS system measures 4.8 metersin diameter; however, when folded, it readily fits within a cylindricalvolume approximately one meter in diameter and three meters in length.Each satellite in the deployed TDRS constellation employs two suchantennae. In addition to the TDRS antenna system, commercial mobilecommunications systems that employ two mesh reflectors, each having anaperture size of twelve meters are also in production. Each of thesereflectors, with folding ribs, is sized to fit within a cylindricalvolume approximately one meter diameter and four and one-half meters inlength. By folding the ribs, the same TDRS-configured volume, moderatelylengthened, can package a reflector over twice the TDRS size.

[0005] There are varieties of other reflector designs in which rigidelements are oriented in either a radial direction from the reflectorcenter or a circumferential direction at the reflector periphery, andmay employ foldable rigid elements to improve packaging. Non-limitingexamples of such prior art antenna structures include the following U.S.Pat. Nos. 5,787,671; 5,635,946; 5,680,145; 5,451,975; 5,446,474;5,198,832; 5,104,211; and 4,989,015.

[0006] In now allowed and copending application Ser. No. 09/330,959, anew and improved structure geometry, either deployable ornon-deployable, includes both radial and circumferential structuralsupport members to support a reflecting surface, such as amesh-configured antenna surface. Employing both radial andcircumferential support members allows the structure to adapt to a widevariety of geomtries and is not limited to only symmetric structures.The structure can include almost any polygonal shape having a uniquegeometry at its periphery. As described in that application, the supportstructure is implemented in either of two embodiments or configurations.Both employ a regular polygonal inner hoop and generally radial struts.The difference between the two configurations involves the location anddesign of the tips or distal ends of the radial struts.

[0007] In the first configuration, distal ends of adjacent radial strutsare hinged together in pairs to form the corner of a triangle, asubtended side of which is one side of an interior hoop structure. Inthe second configuration distal ends of radial struts are not hingedtogether. Interconnecting distal ends of the radial struts in the firstconfiguration reduces internal member loads for structures having arelatively small (generally less than six) number of sides. The secondconfiguration (where the radial struts are not joined together)facilitates implementing relatively large architectures (having four ormore sides); however, there is an increase in internal member loads.

[0008] Although the folded reflector package as described in thecopending application has a reduced stowed length, it would beadvantageous if the stowed length of the folded reflector package couldbe reduced even more. Also, it would be advantageous if the complexityof the structure could be reduced, especially with regard to the variousstruts.

SUMMARY OF THE INVENTION

[0009] The present invention advantageously provides a structuralassembly with a reduced complexity and stowed length of a foldedreflector package. In one aspect of the invention, the structureassembly includes a rigid hoop structure having a plurality of rigidappendages extending outwardly therefrom and forming struts that arearranged to maintain a prescribed structural periphery depth and radialdistance from a center line axis defined by the structural assembly.Each strut is formed from the rigid appendages and includes an optionaltelescoping tube member. A plurality of pivot elements are distributedwithin the hoop structure. Interfaces of the hoop structure and therigid appendages are configured to collapse and deploy the hoopstructure. Tension, flexible, generally inextensible cable members areconnected to the hoop structure and the rigid appendages.

[0010] In yet another aspect of the present invention, the strutsinclude upwardly and downwardly extending struts. The upwardly extendingstruts can comprise a single strut member or pair of strut members. As asingle strut member, the complexity is reduced. The rigid hoop structurecan also be formed as a single member hoop structure and the rigidappendages extending outwardly to form the struts can be configured in atriangular configuration. The rigid appendages can also comprise foldinghoop members which could also be telescoping tube members.

[0011] In yet another aspect of the present invention, a respectivepivot element can include a geared power transmission and hinge assemblythat is configured to transmit power through a moving hinge to effectopening or closing thereof. It can maintain synchronous motion from oneside of the hinge to another throughout all stages of motion of thehinge. Torsion shafts within the rigid elements can transmit power amongplural geared power transmission hinge assembles. As compared to thestructure disclosed in the copending parent application, the presentinvention reduces complexity of the structure by collapsing the twoupper struts, as shown in FIG. 16, into a single strut. The mechanismsto drive the hinges can be similar in terms of gearing and torsion todrive and the linkage at the corner hinges change slightly to drive onlyone top strut as opposed to driving two top struts.

[0012] The stowed length of the folded reflector package is reduced byintroducing the telescoping tube mechanism into top and bottom strutsand optionally into the hoop members.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other objects, features and advantages of the present inventionwill become apparent from the detailed description of the inventionwhich follows, when considered in light of the accompanying drawings inwhich:

[0014]FIG. 1 is a diagrammatic perspective view of a six-sided supportarchitecture, deployed by means of three side units formed of foldablehoop members or legs of a first embodiment of the present invention.

[0015]FIG. 2 is a diagrammatic perspective view of a three-sided supportarchitecture in accordance with a second embodiment of the presentinvention.

[0016] FIGS. 3-7 show the support architecture of FIG. 1 duringsuccessive phases of its deployment.

[0017] FIGS. 8-12 show the support architecture of FIG. 2 duringsuccessive phases of its deployment.

[0018]FIG. 13 shows the configuration of a respective side unit of theembodiment of FIG. 1.

[0019]FIG. 14 shows the configuration of a respective side unit of theembodiment of FIG. 2.

[0020]FIG. 15 a diagrammatic perspective view of a twelve-sided supportarchitecture formed of six side units of the first embodiment of thepresent invention.

[0021]FIG. 16 is a diagrammatic perspective view of a six-sided supportarchitecture formed of six side units of the second embodiment of thepresent invention.

[0022]FIG. 16A is another diagrammatic perspective view of an improvedsix-sided support architecture similar to that support architectureshown in FIG. 16, except the double strut members as an upwardlyextending strut shown in FIG. 16 have been replaced with a single memberas shown in FIG. 16a.

[0023]FIG. 17 illustrates the use of a four-sided support architecturein accordance with the second embodiment of the present invention tosupport a tensioned cord truss arrangement for a metallic mesh,reflective surface.

[0024]FIG. 18 is an exploded view depicting the overall assembly of thestructure of FIG. 17.

[0025]FIGS. 19, 19A, 20 and 21 show details of a hinge installable at arespective mid-side of a linear hoop member of the second embodiment ofthe invention.

[0026]FIGS. 22 and 23 show details of a hinge that is installable at arespective corner joint of the hoop structure of the second embodimentof the invention.

[0027]FIG. 24 shows details of a respective geared corner hinge and thedetails of a folding radial member with its distal and mid hinge jointsfor the first embodiment of the invention.

[0028]FIG. 25 shows details of a hinge that is installable at arespective mide side of the hoop structure of the first embodiment ofthe invention.

[0029]FIGS. 26, 27 and 28 illustrate an alternative synchronizationscheme for the configuration of a hoop structure of the secondembodiment of the invention.

[0030]FIGS. 29 and 30 show the type of telescoping tubes that can beused as strut members in the present invention.

[0031]FIGS. 31 and 32 show the support architecture in a 50% deployedposition (FIG. 31) and 100% deployed position (FIG. 32), where the finalgeometry is the same regardless of the drive system used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The present invention will now be described more fullyhereinafter with reference to the accompanying drawings, in whichpreferred embodiments of the invention are shown. This invention may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Like numbers refer to like elements throughout.

[0033] Attention is initially directed to FIG. 1, which is adiagrammatic perspective view of a six-sided support architecture,deployed by means of three side units formed of foldable hoop members orlegs of a first embodiment of the present invention. In the embodimentof FIG. 1, distal ends of radial strut elements are joined together bymeans of outer perimeter hinge joints. In the diagrammatic illustrationof FIG. 1, bold lines represent the rigid elements of the supportstructure, and cable or rope-like (tension only) elements arerepresented by thinner lines.

[0034] In the non-limiting example of a six-sided support architecture,the embodiment of FIG. 1 is formed of three side sections, with arespective side section (shown in detail in FIG. 13, to be described)being configured of a pair of folding hoop members or legs 21. Thelength of a respective hoop member of leg 21 is the same as that ofother hoop members and is generally the same length as a respectivenon-segmented or continuously rigid upper radial strut 13. The hoopelements 21 are hinge-connected to one another in end-to-end fashion athinge joints 23 and 25, so as to define a regular polygonal shaped hoopstructure.

[0035] In addition to providing attachment points to the hoop members 21for adjacent pairs of the non-segmented upper radial struts and adjacentpairs of segmented upper radial struts, each hinge joint 23 and 25 iscoupled to an interior end 16 of a further radial bottom strut 18.Synchronously driving the corner hinges 23 and 25 (shown in detail inFIGS. 24 and 25, to be described) enables the structure to fold in amanner consistent with powered, synchronous deployment, as will bedescribed below with reference to FIGS. 3-7.

[0036] Pursuant to the first embodiment of the invention, distal ends 11of each of a plurality (e.g., pair) of adjacent upper non-segmentedradial struts 13, and distal ends 12 of each of a plurality (e.g., pair)of adjacent upper segmented radial struts 14 are hinged together bymeans of passive (non-driven) hinges installed at a plurality of outerperimeter corner joints 15 (to be described with reference to FIG. 24).

[0037] Each of the upper segmented radial struts 14 is comprised of apair of radial strut elements 14-1 and 14-2, that are connected at afolding mid-strut hinge joint 14-3 (shown in detail in FIG. 24, to bedescribed). The mid-strut hinge joints 14-3 allow a respectivenon-segmented upper radial strut 13 to be folded about hoop corner hingejoints and stowed generally parallel to a respective hoop member 21 ofthe interior, polygonal folded hoop structure 20. Interior ends 17 ofthe upper radial struts 13 and 14 extending from adjacent outerperimeter joints 15 are connected to the hoop members 21 of the hoopstructure 20, by means of a plurality of multi-axis driven hoop hingejoints 23 and 25. It should be noted that the hoop hinges 23 and 25,while similar in function, are differently configured, as shown in FIGS.24 and 25. Hinge joints 23 support the non-segmented upper radial struts13, while hinge joints 25 support the segmented upper radial struts 14.In addition, hinge joints 23 and 25 may comprise relatively non-complexpin joints, to allow the structure to be deployed into itsthree-dimensional shape with relatively simple kinematics.

[0038] Circumferentially tensioned, upper cords 31 of an uppertensioning ring 30 tie together successive ones of the plurality ofouter perimeter corner joints 15, while circumferentially tensioned,lower cords 41 of a lower tensioning ring 40 tie together distal ends 19of successive ones of the plurality of the lower or bottom radial struts18. Additional, tension-only cord elements 45 interconnect successivelyadjacent outer perimeter corner joints 15 at the distal ends 11 of theupper radial struts 13 and 14 with distal ends 19 of the lower radialstruts 18. Tensioning cord elements 45 and the upper and lowertensioning rings 30 and 40 function to stabilize the distal ends of theupper and lower radial struts and impart stiffness to the entirestructure.

[0039]FIG. 2 is a diagrammatic perspective view of a three-sided supportarchitecture in accordance with a second embodiment of the presentinvention, wherein distal ends 51 of upper radial strut elements 50 anddistal ends 61 of lower radial strut elements 60 are not hinged togetherto form outer perimeter hinged corner joints. Instead, the distal ends51 of upper radial strut elements 50 are joined together bycircumferential tensioning cords 55 of an upper tensioning ring 57.Also, distal ends 61 of lower radial strut elements 60 are joinedtogether by circumferential tensioning cords 65 of a lower tensioningring 67.

[0040] In addition, a respective side 71 of an interior multi-sided(polygonal) hoop structure 70, from side corner joints 73 of which theradial struts 50 and 60 extend, is comprised of a pair of hoop members81 and 82, that are joined together at a midpoint 83 of the side 71 bymeans of a driven hinge 85 (shown in detail in FIGS. 19-21,to bedescribed). Interior ends 52 of the strut elements 50 and interior ends62 of the strut elements 60 are secured to side corner joints 73 of themulti-sided hoop structure 70 by means of a plurality of multi-axisdriven hoop hinges 75 (shown in detail in FIGS. 22 and 23, to bedescribed). Each of the driven hoop hinges 75 and 85 is synchronouslydriven to enable the structure to fold in a manner consistent withpowered, synchronous deployment, as will be described below withreference to FIGS. 8 to 12.

[0041] Additional tension-only cord elements 56 are used to interconnectsuccessively adjacent distal ends 51 of the upper radial struts 50 withsuccessively adjacent distal ends 61 of the lower radial struts 60. Asin the first embodiment, these tensioning cord elements 56 and the upperand lower tensioning rings 57 and 67, respectively, function tostabilize the distal ends of the radial struts and impart stiffness tothe entire structure.

[0042]FIGS. 3 through 7 diagrammatically illustrate the deploymentsequence for the foldable hoop structure of the first embodiment of theinvention shown in FIG. 1, beginning with its stowed configuration (FIG.3), through successive 25%, 50%, 75% partially deployed conditions, tothe fully deployed condition (FIG. 7) of the hinged hoop architecture.In order to avoid complicating the drawings, only the rigid radialstruts and hoop members are shown in FIGS. 3-7.

[0043] As shown therein, by synchronous operation of the driven hinges23 and 25, the hoop members 21 deploy from a generally verticaldirection in their stowed condition of FIG. 3 to a generally horizontaldirection in their fully deployed condition of FIG. 7. In the 50%deployed condition of FIG. 5, the non-segmented upper radial struts 13have pivoted or rotated outwardly from the hoop corner hinge joints 23,while the two halves 14-1 and 14-2 of the segmented upper radial struts14 have partially opened from their folded stowed condition. The lowerradial struts 18 are also pivoted outwardly by the driven hinges 23 and25 from their generally vertical condition in the stowed state of FIG. 3to their deployed condition in FIG. 7. FIG. 13 shows the configurationof a side unit of the embodiment of FIG. 1, as fully deployed in FIG. 7.

[0044] In the fully deployed condition of FIG. 7, the two halves 14-1and 14-2 of a respective segmented upper radial strut 14 have fullyopened, so as to form a generally equilateral triangle structure with anadjacent non-segmented radial strut 13 and a respective hoop member 21.The lower radial struts 18 are also rotated or pivoted outwardly by thedriven hinges 25 from their vertical condition in the stowed state ofFIG. 3 to their deployed condition in FIG. 7. As pointed out above, thedistal end 19 of the lower radial strut 18 provides a cord attachmentpoint to distributing the loads of the upper and lower tensioning rings.The folded struts 14 also improve the distribution of deployed loads,especially in the upper tensioning ring.

[0045]FIGS. 8 through 12 diagrammatically illustrate the deploymentsequence for the foldable hoop structure of the second embodiment of theinvention shown in FIG. 1, beginning with its stowed configuration (FIG.8), through successive 25%, 50%, 75% partially deployed conditions, tothe fully deployed condition (FIG. 12) of the hinged hoop architecture.Again, as in the deployment sequence of FIGS. 3-7, to avoidunnecessarily complicating the drawings, only the rigid elements areshown in FIGS. 8-12. No flexible, tension-only elements are shown.

[0046] As shown therein, by synchronous operation of the driven cornerand midpoint hinges 75 and 85, respectively, the hoop members 71 deployfrom a generally vertical direction in their stowed condition of FIG. 8to a generally horizontal direction in their fully deployed condition ofFIG. 12. In the 50% deployed condition of FIG. 10, the upper radialstruts 50 and lower radial struts 60 have pivoted or rotated outwardlyfrom the corner hinge joints 75, while the two hoop member halves 81 and82 of a respective side 71 of the interior multi-sided (polygonal) hoopstructure 70 have partially opened from their folded stowed condition.

[0047] In the fully deployed condition of FIG. 12, the two halves 81 and82 of a respective hoop member 71 have fully unfolded into a generallycollinear configuration, so as to form an equilateral triangle structurewith unfolded collinear halves of the other two adjacent hoop members71. Also, the respective upper and lower radial struts 50 and 60 are nowfully rotated or pivoted outwardly by the driven corner hinges 75 fromtheir generally vertical condition in the stowed state of FIG. 8 totheir deployed condition of FIG. 12. FIG. 14 shows the configuration ofa respective side unit of the embodiment of FIG. 2, as deployed in FIG.12.

[0048] The two embodiments of FIGS. 1 and 2 appear to be different, inthat the first embodiment (FIG. 1) forms a six-sided polygon, while thesecond embodiment (FIG. 2) forms a triangle. However,each of theseembodiments is formed of a three ‘side units’, respective ones of whichare shown in FIGS. 13 and 14. Each side unit is based upon hoop membersor legs, shown at 21 in FIG. 13 and at 71 in FIG. 14). The differencesbetween the two embodiments derive from the geometries of the hinges 25of FIG. 13 and 83 of FIG. 14 and, as described previously, theimplementations of the upper radial struts 13 and 14 of FIG. 13 andupper radial struts 50 in FIG. 14.

[0049] In addition, the hinge 25 of the first embodiment of FIG. 13supports a lower or bottom radial strut 18, while in the secondembodiment of FIG. 14, the hinge 83 does not supprt a lower radialstrut. Geometrically, the hinge 25 of the first embodiment of FIG. 13incorporates a bend that is generally equal in angle to the bend of thecorner hinge 23, so as to form a generally hexagonally shaped structure.Configuring the side units of the respective embodiments in this mannerallows them to be used as ‘building blocks’ that can be replicated andinterconnected around a centerline of the structure, to realize apolygonal architecture of an arbitrary number of sides.

[0050] Thus the size of the structure may be increased by adding moreside units. As a non-limiting example, for structures larger than thoseof FIGS. 1 and 2, the number of hoop sides may be increased to twelve,using six of the side units of the first embodiment, as showndiagrammatically in FIG. 15), or to six, using six of the side units ofthe second embodiment, as shown diagrammatically in FIG. 16). As thenumber of sides of the interior hoop increases, the stowed lengthdecreases, and the stowed diameter increases. This trade-off provides areasonable degree of design flexibility to adapt to a wide range ofstowed volume requirements.

[0051] The need for improved load distribution, hence the need for theadditional elements of the first embodiment, diminishes with an increasein the number of sides of the hoop structure. The two hoop structureconfigurations described above allows the choice of a structure havingfewer powered hinges in situations where a longer stowed length isafforded. In general, given a required deployed diameter, the stowedlength of the configuration of the first embodiment will beapproximately twice that of the configuration of the second embodiment;however, it will employ only half the number of powered or drivenhinges.

[0052]FIG. 16A shows a new and improved configuration similar to FIG.16, except the two top strut members have been collapsed into a singletop strut member. The complexity of the structure is reduced and themechanisms to drive the hinges can be identical in terms of gearing andtorsion tube drive. The linkage at the corner hinges can change slightlyto drive only one top strut member, as opposed to driving two top strutmembers.

[0053] As diagrammatically illustrated in assembled view of FIG. 17, andthe exploded view of FIG. 18, which show a four-sided hoop supportarchitecture 90 in accordance with the second embodiment of the presentinvention, mounting a reflective surface to the hoop structure isstraightforward. The four-sided hoop support configuration of FIGS. 17and 18 employs a standard tensioning cord truss attachment framework 100to attach a surface, such as an electrically conductive (metallic) meshreflective surface (not illustrated) that is reflective ofelectromagnetic energy, to underlying hoop support structure 90.

[0054] Advantageously, in the course of assembling the tensioning cordtruss framework 100 and attaching it to the support structure 90, thereare relatively few interfaces between the hoop support structure 90 andthe cord truss network 100. This facilitates parallel, yet independent,assembly of the antenna surface and the hoop support structure. As shownin the exploded view of FIG. 18, there are two sets of attachment pointsor interfaces between the cord truss network 100 and the hoop structure90: 1-the distal ends 51 of the upper struts 50; and 2-the distal ends61 of the lower struts 60. There is also an attachment point at thecenter 101 of the cord truss network 100. This means that for thefour-sided configuration of FIGS. 17 and 18 only thirteen interfacepoints are required.

[0055] In the course of manufacture of the embodiment of FIGS. 17 and18, individual cord truss elements 111 of an upper cord truss assembly110 are manufactured as individual generally planar shaped structures.These planar shaped structures elements 111 are then integrated into atwo-dimensional network 120, along with the material used to reflect andfocus energy. For an RF antenna this material may comprise a tensioned,metal mesh fabric. An arrangement of network-to-structure cords 130 isassembled to tooling and the cord truss network 120 is attached.

[0056] At this point, the entire reflective component of the system andits supporting cord-truss assembly is ready to be geometricallypositioned so as to conformed with a prescribed accuracy specification.The surface can be set on the tooling while preparations of thestructure are performed in parallel. Once the reflective surface isproperly adjusted and the structure is assembled, the surface can beremoved from the tooling and integrated with the structure. A finaladjustment to correct differences between the tooling and the as-builtstructure can be readily carried out by adjusting only the interfacepoints. These relatively few interface points also provide practicallocations for implementation of in-orbit or remote adjustment, toimprove or correct for in-service disturbances of the deployedstructure.

[0057] As described above, to deploy the hoop structure from its stowedcondition to its fully deployed state in a slow, controlled andsynchronized fashion, the present invention uses a gear driven hingearrangement configured as shown in FIGS. 19, 20 and 21, and installableat the hoop mide side joints 83 of the second embodiment of FIG. 2, andgear driven corner joint hinge arrangements, configured either as shownin FIGS. 22 and 23 for installation at corner joints 75 for the secondembodiment of the invention, or configured as shown in FIGS. 24 and 25for installation at corner joints 25, for the first embodiment of theinvention.

[0058] More particularly, FIG. 19 shows a front view of the linear hoopgear-driven hinge arrangement for a fully deployed condition (collinearalignment) of the hoop elements that extend on either side of a midhinge joint.

[0059]FIGS. 20 and 21 show rear views of this linear hoop gear drivenhinge arrangement. In each of the figures the bold arrows 201 and 202indicate the closing (stow) direction of respective ones of generallycylindrically configured hoop segments 71-1 and 71-2.

[0060] Respective synchronization gears 171 and 172 are rigidly affixedto or solid with respective hoop members 71-1 and 71-2. Hoop members71-1 and 71-2 attach to longitudinal platform members 181 and 182,respectively, via pinned pivots 203 and 204. These gears and platformmembers maintain the hoop members in dynamic and static symmetry(synchronization) with respect to each other at each stage ofdeployment. Stated another way, the angle between the platform member181 and hoop member 71-1, and the angle between platform member 182 andhoop member 71-2 will be the same throughout all stages of deployment.

[0061] The force used to deploy (or stow) the hinge is provided by adrive gear 190 that is rigidly attached by means of a gear housing 192to hoop member 71-1 and the synchronization gear 171. Motion of thedrive gear 190 turns rotates a platform gear element 183 to open (orclose) the platform 182 with respect to the hoop member 71-1. By virtueof the synchronization gears 171 and 172, the angle between hoop member71-1 and platform member 181 is transferred to the angle between hoopmember 71-2 and platform member 182, and motion is transmitted from oneside of the hinge to the other.

[0062] Ideally, for a space-deployed environment (such as a satelliteantenna), where gravitational forces are nearly zero, the force requiredto open the hinge should be minimal. However, for terrestrialapplications, deployment loads may be significant. To provide thecapability to maximize deployment force, a driven gear train 184 havinga large (several thousand to one) gear ratio using simple spur gears ina clockwork-like mechanism is provided.

[0063] In order to synchronize the operation of each hinge with that ofits neighbors, a pair of respective torsion tubes 207 and 208 aresupported internal to the hoop members 71-1 and 71-2 to transmit rotarymotion from one end of a hoop member to the other. As shown in FIG. 19A,the torsion tube 208 inside the hoop member 71-2 drives a set of bevelgears 211 and 212. A spur gear 205, rigidly attached to bevel gear 212,rotates a gear 214. This motion is transmitted via gear 196 toultimately turn, through the bevel gear set 216, 215 the torsion tube207. By this arrangement torque motion is transmitted through arespective hinge to power the next neighboring hinge. This rotation alsoprovides the motive force driving the input to the gear train 184, asshown in FIG. 20.

[0064]FIG. 21 provides an enlarged view of FIG. 20, showing the input tothe gear train 184, in which both the platform gear 183 and the torquetransmission gear 196 have been removed for clarity. The input to thegear train 184 is from the troque tube 207 through bevel gear 194 tofollower 216 aand its integral spur gear 195. Spur gear 195 is the firstgear of the multi-pass gear train 184. The multi-pass gear train 184consists of cascaded, back-to-back spur gears similar to a typicalclockwork mechanism. The gears, secured in housing 192, are able toprovide a relatively large gear reduction (e.g., several thousand toone) between the torque tube 207 and the platform drive gear 190. As aresult, very little torqing of torque tube 207 is required to open thehinge. This mechanism provides a means to deliver deployment energy tothe hinge, as well as transmit energy through the hinge to power itsneighboring hinge. Since all driven hinges are tied together viainternal hoop torsion tubes, the hinges are effectively geared andsynchronized.

[0065] The hinge drive mechanism described above for a hoop mid hingemay be readily adapted for a corner hinge, as shown diagrammatically inFIGS. 22 and 23, which are respective front and rear views of a cornerhinge joint for the fully deployed condition of the second embodiment ofthe invention. Except for the inherent bend at a corner joint, thearchitecture and operating mechanism of a respective corner joint hingeis identical to that for a mid-hinge. In the figures, bold arrows 231indicate the direction of motion to close (stow) the hoop segments 71-2and 71-1 on opposite side of a corner hinge joint 75. The gearing isvirtually the same as that described for the mid-hinge configurationshown in FIGS. 19-21, described above. The gear ratios among the hingesare identical in order to maintain synchronization, so that all of thehinges (both corner and mid-strut) will open the same angular amount inthe course of going from a closed condition to an open or fully deployedcondition. For a corner hinge joint used for the second embodiment ofthe invention (shown in FIG. 2, described above), a respective cornerhinge 75 provides the force and kinematic linkage to open or deploy eachof the struts (two adjacent upper struts 50L and 5OR and one lower orbottom radial strut 60). FIGS. 22 and 23 show these three struts andtheir associated linkages.

[0066] The relationships among hoop members 71-2, 71-1 and truts 50L,5OR and 60, hinged at the corner joint 75 are illustrated in FIG. 23.The hoop members 71-2 and 71-1 are controlled directly by gearingdescribed for the mid-hinge of FIGS. 19, 20 and 21. The bottom strut 60contains a clevis 241 and is driven by a link 243 that is connected to asynchronization gear 245 via a clevis 247. For the upper strut 50L, apivot axis support 251 is firmly attached to the hoop member 71-2. Asthe hoop member 71-2 moves with respect to the corner hinge platform252, a platform clevis 254, a link 256 and a strut clevis 258 define theposition of the upper strut 50L. The other upper strut 5OR is driven byan identical, mirror image linkage.

[0067] The hinge and linkage mechanisms for deploying the hoop supportstructure in accordance with the first embodiment of the invention ofFIG. 1 are diagrammatically illustrated in FIGS. 24 and 25. It should benoted that the structure illustrated in FIG. 24 is re-oriented withrespect to that shown in FIG. 1, in order to more clearly show thedetails of the two hinges 23 and 25. Bold arrows 251 and 253 show thedirection of motion to close the hoop members that connect to the drivenhinge. As described above, and as shown in FIG. 24, the upper strutarrangement of the first embodiment differs from that of the secondembodiment by the fact that distal ends of each of a pair of adjacentnon-segmented upper radial strut elements 13, and distal ends of each ofa pair of adjacent segmented upper rigid radial strut elements 14 arehinged together by means of passive (non-driven) hinges 260 installed ata plurality of outer perimeter corner joints 15.

[0068] In addition, each segmented upper radial strut 14 is formed of apair of radial strut elements 14-1 and 14-2, that are interconnected bya folding passive mid-strut hinge joint 14-3 shown in FIG. 24. Thesemid-strut hinge joints 14-3 allow an adjacent non-segmented upper radialstrut element 13 to be folded about the hoop corner hinge joints 23 andstowed generally parallel to the hoop members 21, as described above.FIG. 24 shows how the required kinematic deployment motion of the firstembodiment is accomplished with three simple pivot joints.

[0069] Pivot joint 260 provides a hinge connection between the distalend of a non-segmented upper radial strut element 13 and the distal endof an adjacent segmented upper rigid radial strut elements 14. A simplepin pivot joint 261 pivotally connects interior ends of the upper radialstrut elements 13 and 14 to the corner joints 25 of the hoop members 21.Pivot joint 14-3 provides a mid-strut hinge connection at the foldingpassive mid-strut joint between upper radial strut elements 14-1 and14-2.

[0070] The configuration of each of the synchronously driven mid-hinges25 of the first embodiment shown in FIGS. 24 and 25 is very similar tothat of the corner hinge of the second embodiment shown in FIGS. 22 and23. The segmented upper radial strut 14-2R is driven via linkage 254,256 and 258, as shown in FIG. 25. A mirror or complementarily configuredlinkage is used to drive the other upper radial strut 14-2L. The hingehoop members 21 and the bottom strut 18 are connected in the same manneras hoop members 71 and the bottom radial struts 60, and controlled asdescribed with reference to the driven corner hinges of FIGS. 22 and 23.

[0071] Powering the deployment of the support structure may be readilyachieved by a single electric motor driving a torsion tube anywherealong its length within a hoop member, such as at or near a hinge orwithin a hoop member, as shown at 234 in FIG. 22. A simple pinionattached to the motor output can drive a spur gear rigidly attached tothe torsion tube. Advantageously, because of the torsion tube linkageand synchronized gearing within and between all the hinges, a singlemotor is able to deploy the entire structure. Alternatively, multiplemotors may be installed for deployment redundancy.

[0072]FIGS. 26, 27 and 28 illustrate an alternative configuration of thehoop structure of the second embodiment of the invention, having hingesinstallable at respective mid-hoop and corner regions. This alternativeconfiguration comprises a set of four-bar linkages 300 and 400, havinghoop members 301, 302, 303 and 304, and drive platforms 305 and 405.This embodiment of the invention is readily deployed by driving one ofthe hinges with a mechanism capable of generating sufficient force, suchas the geared mechanisms described above. Since all the hinges aresynchronized and linked via the four-bar linkages, all hinges willdeploy simultaneously with the driven linkage. Bold arrows 310 and 410indicate the direction for closing (stowing) the hoop members. The upperhoop members 303 and 304 maintain platforms 305 and 405 parallel to oneanother.

[0073] An advantage of the alternative embodiment of FIGS. 26-28 is areduction in hardware complexity by removal of the gearing mechanisms.However, this requires doubling the number of elements within the hoopitself, which may not be a desirable trade-off from a cost or packagingaspect. Further, the internal member loads required to deploy thestructure are substantially larger than for the geared design.

[0074] FIGS. 29-32 illustrate an improved enhancement to the structurethat significantly reduces the stowed length of the folded reflectorpackage. The telescoping tube mechanism is incorporated into top andbottom strut members and optionally into the hoop members themselves. Bytelescoping these members, the stowed length is reduced. The type ofcollapsing structure can be selected by those skilled in the art. Thisincludes different telescoping members as known to those skilled in theart, including similar antenna types of members and other telescopingmembers.

[0075] As will be appreciated from the foregoing description, thepresent invention provides a new and improved compactly stowable andspace-deployable energy directing surface support architecture, thatincludes both radial and circumferential structural support members, fordeploying an unfurlable surface, such as a conductive mesh-configuredantenna reflector surface. The architecture of the present inventionprovides benefits in terms of weight and number of rigid elements. Manyfocusing structures, such as reflectors, require some amount of physicaldepth at their periphery. As a consequence, most hoop designs use twohoops—an upper hoop and a lower hoop—to supply this depth, which ismaintained by installing additional vertical members to spatiallyseparate the two hoops.

[0076] The generally hoop-configured support structure of the inventionlocates a single hoop at an interior position of the structureperiphery, thereby reducing the overall length of the rigid members ofwhich the hoop is formed. As described above the invention employs cordor other cable-like elements at the periphery of the radial struts astension only elements. The total radial strut length is generally lessthan the overall lengths of the rigid members that are used to maintainstructural periphery depth in a conventional double hoop designs. Byincorporating these features, the total physical length of rigid membersthat collapse for storage and transport is reduced over prior art hoopconfigurations. This reduces overall structure complexity and enhancessystem reliability. Fewer rigid members also reduces the overallstructural mass.

[0077] The architecture of the invention enjoys similar advantages overconventional designs using rigid radial elements. In general, the singlehoop structure of the invention has a total rigid member length lessthan a radial design with eight or more rigid radial elements. Whendepth at the periphery of the deployed surface is considered, thepresent invention provides a considerably more efficient architecturethan one obtained by adding more elements to a radial rib configuration.For example, to implement the 4.8 meter TDRS reflector structurereferenced above, the present invention can be folded into a 0.3 meterdiameter by 1.6 meter long cylindrical volume. Moreover, to implement atwelve meter reflector, a folded rib design using the structure of theinvention is able to fit within a 0.6 meter diameter by 4 meter longcylindrical volume.

[0078] These characteristics of reduced numbers and lengths of rigidmember apply equally to both non-folding and deployable forms of thestructure. The rigid members (struts) of the support architecture of theinvention are deployed to their open condition using a minimal number ofand only two basic types of hinges. The driven hinges provide theessential power and synchronization to deploy the hoop and its struts ina slow and controlled manner. The nature of the deployment mechanismalso provides a high motive force to load structural cords and tensionedsurface elements, such as the electrically conductive (e.g., metallic)mesh often employed in reflector geometries. The high force developed bythe driven hinge mechanism improves deployment reliability, by improvingthe capability to drive through any unforeseen snags or other anomaliesthat may occur in tensioned mesh reflectors.

[0079] By combining a geometry that reduces the total length of rigidelements, using tension-only elements where practical, and minimizingthe number of hinges, the present invention provides a deployablesupport system that is less complex, lighter and folds to a more compactpackage than typical prior art configurations. Although the lightweight,compactly folding geometry of the invention is particularly suited forspace deployed applications, it may also be used in systems, wherefixed, non-deployable devices need to be extremely lightweight,including ground-based structures.

[0080] Using standard space qualified materials, the stability of theinventive structure will meet requirements for a precise reflectorshape. The geometry and small mass of the architecture of the inventionprovide significant stiffness and minimal inertia to reduce dynamicdistortions. Also, using low thermal coefficient of expansion materialsensures maintenance of the geometric precision when subjected to theextreme thermal environment of space. The antenna architecture of thepresent invention readily implements standard techniques to support atensioned metal mesh, but is not limited to only these types ofsurfaces. The inventive structure, especially the non-foldingconfiguration, can support any type of surface, whether solid or porous,tensioned or not.

[0081] While several embodiments have been shown and described inaccordance with the present invention, it is to be understood that thesame is not limited thereto, but is susceptible to numerous changes andmodifications as known to a person skilled in the art, and therefore donot wish to be limited to the details shown and described herein butintend to cover all such changes and modifications as are obvious to oneof ordinary skill in the art.

[0082] Many modifications and other embodiments of the invention willcome to the mind of one skilled in the art having the benefit of theteachings presented in the foregoing descriptions and the associateddrawings. Therefore, it is to be understood that the invention is not tobe limited to the specific embodiments disclosed, and that themodifications and embodiments are intended to be included within thescope of the dependent claims.

That which is claimed is:
 1. A structural assembly comprising: a rigidhoop structure having a plurality of rigid appendages extendingoutwardly therefrom and forming struts that are arranged to maintain aprescribed structural periphery depth and radial distance from acenterline axis defined by said structural assembly, wherein at leastone strut is formed as a telescoping tube member; a plurality of pivotelements distributed within said hoop structure, and at interfaces ofsaid hoop structure and said rigid appendages, and being configured tocollapse and deploy said hoop structure; and tensioned, flexible,generally inextensible cable members connected to said hoop structureand said rigid appendages.
 2. A structural assembly according to claim1, wherein said rigid hoop structure is formed as a single member hoopstructure.
 3. A structural assembly according to claim 1, wherein saidrigid appendages extending outwardly to form said struts are configuredin a triangular configuration.
 4. A structural assembly according toclaim 1, wherein said struts further comprise upwardly and downwardlyextending struts.
 5. A structural assembly according to claim 4, whereineach of said upwardly extending struts comprise a pair of strut members.6. A structural assembly according to claim 4, where each of saidupwardly extending struts comprise a single strut member.
 7. Astructural assembly according to claim 4, wherein adjacent upwardlyextending struts are joined at distal ends thereof.
 8. A structuralassembly according to claim 4, wherein said upwardly extending strutsare spaced apart at distal ends thereof.
 9. A structural assemblyaccording to claim 1, wherein said rigid appendages further comprisefolding hoop members.
 10. A structural assembly according to claim 9,wherein said folding hoop members comprise at least one telescoping tubemember.
 11. A structural assembly according to claim 1, wherein saidhoop structure includes a plurality of rigid elements joined end-to-endto form a polygon, such that each end-to-end junction forms a corner ofsaid polygon.
 12. A structural assembly according to claim 1, whereinsaid tensioned, flexible, generally inextensible elements include cordsthat are connected to said struts to maintain a prescribed length andforce between distal ends of said struts and between end-to-endjunctions.
 13. A structural assembly according to claim 1, wherein saidpivot elements include pivot elements at corners of said hoop structure,configured to fold said rigid elements from a deployed polygonal shapeto a stowed orientation that is generally parallel to said centerlineaxis.
 14. A structural assembly according to claim 13, wherein saidpivot elements at said corners are configured to fold said appendages toan orientation that is generally parallel to said centerline axis.
 15. Astructural assembly according to claim 14, further including pivotelements at midpoints of said rigid elements, that are configured tofold said rigid elements into an orientation that is generally parallelto said centerline axis.
 16. A structural assembly according to claim15, further including pivot elements at midpoints of selectedappendages, and configured to fold said selected appendages into anorientation that is generally parallel to said centerline axis.
 17. Astructural assembly according to claim 1, further including a network oftensioned cords having pluralities of generally horizontal top andbottom components connected with generally vertical cords therebetweenforming a planar truss, and being supported by said appendages.
 18. Astructural assembly according to claim 17, further including an energydirecting surface supported by said network of tensioned cords.
 19. Astructural assembly according to claim 1, wherein a respective pivotelement comprises a geared power transmission and hinge assembly that isconfigured to transmit power through a moving hinge to effect opening orclosing thereof, and to maintain synchronous motion from one side ofsaid hinge to another throughout all stages of motion of said hinge, andincluding torsion shafts within said rigid elements that transmit poweramong plural geared power transmission hinge assemblies.
 20. Astructural assembly according to claim 19, wherein a respective gearedpower transmission and hinge assembly includes a pair of gears rotatableabout respective pivot axes, and coupled with a torsion shaft.
 21. Astructural assembly according to claim 19, wherein a respective gearedpower transmission and hinge assembly includes a rigid frame thatsupports and maintains a pair of hinges in a constant geometricrelationship to each other through all stages of hinge motion.
 22. Astructural assembly according to claim 21, wherein a respective gearedpower transmission and hinge assembly further includes an idler gearsituated between said gears of said pair to effect a rotation reversalin a deployment transmission path.
 23. A structural assembly accordingto claim 1, wherein said rigid hoop structure comprises a multi-sidedhoop structure, a respective side of which is configured as a four-barlinkage having upper and lower hoop members coupled at ends thereof to aplatform linkage, a respective lower hoop member attaching to a lowerpart of said platform linkage, and a respective upper hoop memberattaching to an upper part of said platform linkage, a respectiveplatform linkage containing four pivots attached to two pairs of upperand lower hoop members.
 24. A structural assembly comprising: a rigidhoop structure having a plurality of rigid appendages extendingoutwardly therefrom and forming upwardly and downwardly extending strutsthat are arranged to maintain a prescribed structural periphery depthand radial distance from a centerline axis defined by said structuralassembly, wherein each upwardly extending strut comprises a single strutmember; a plurality of pivot elements distributed within said hoopstructure, and at interfaces of said hoop structure and said rigidappendages, and being configured to collapse and deploy said hoopstructure; and tensioned, flexible, generally inextensible cable membersconnected to said hoop structure and said rigid appendages.
 25. Astructural assembly according to claim 24, wherein said rigid hoopstructure is formed as a single member hoop structure.
 26. A structuralassembly according to claim 24, wherein said rigid appendages furthercomprise folding hoop members.
 27. A structural assembly according toclaim 26, wherein said folding hoop members comprise at least onetelescoping tube member.
 28. A structural assembly according to claim24, wherein said hoop structure includes a plurality of rigid elementsjoined end-to-end to form a polygon, such that each end-to-end junctionforms a corner of said polygon.
 29. A structural assembly according toclaim 24, wherein said tensioned, flexible, generally inextensibleelements include cords that are connected to said struts to maintain aprescribed length and force between distal ends of said struts andbetween end-to-end junctions.
 30. A structural assembly according toclaim 24, adjacent upwardly extending struts are joined at distal endsthereof.
 31. A stowable and deployable support architecture to which anenergy directing surface is attachable, comprising a multi-sidedfoldable hoop structure having hoop members, a plurality of foldablejoints, and generally radial struts connected to hoop members and thatextend from and are foldable about corner joints of said multi-sidedhoop structure, wherein said struts comprise at least one telescopingtube member and at least one drive mechanism coupled to foldable jointsof said multi-sided hoop structure, and being operative to unfold anddeploy said multi-sided foldable hoop structure and said plurality ofgenerally radial telescoping struts, and thereby said energy directingsurface from a folded, stowed configuration to an unfolded, deployedconfiguration.
 32. A stowable and deployable support architectureaccording to claim 31, wherein distal ends of respective pairs ofadjacent radial struts that extend from corner joints of saidmulti-sided foldable hoop support structure are hinged together, andwherein mid-points of alternate segmented radial telescoping struts arehinged together by folding mid-strut hinge joints, so as to allow hingedtogether radial telescoping strut pairs to be folded about said cornerhinge joints and stowed parallel to a respective hoop member of a sideof said multi-sided foldable hoop structure, said radial struts beingconnected to said corner joints by multi-axis, synchronously drivenhinges.
 33. A stowable and deployable support architecture according toclaim 32, further including an upper tensioning ring of tensioned uppercords that join together distal ends of upper radial struts, and a lowertensioning ring of tensioned lower cords that joint together distal endsof lower radial struts, and tension-only cord elements interconnectingdistal ends of upper radial struts with distal ends of lower radialstruts, so as to stabilize distal ends of said radial struts and impartstiffness to said support architecture in its deployed state.
 34. Astowable and deployable support architecture according to claim 31,wherein a respective side of said multi-sided hoop structure issegmented into a pair of hoop members that are joined together by adriven hinge joint, upper and lower radial struts are coupled to cornerjoints of said multi-sided hoop structure by multi-axis driven hingejoints, and including a hinge drive mechanism that is configuredsynchronously drive each driven hinge joint.
 35. A stowable anddeployable support architecture according to claim 34, wherein distalends of said radial struts are not hinged together, and furtherincluding an upper tensioning ring of tensioned upper cords that jointogether distal ends of upper radial struts, a lower tensioning ring oftensioned lower cords that joint together distal ends of lower radialstruts, and tension-only cord elements interconnecting distal ends ofupper radial struts with distal ends of lower radial struts, so as tostabilize distal ends of said radial struts and impart stiffness to saidsupport architecture in its deployed state.
 36. A method ofmanufacturing a stowable and deployable energy director comprising thesteps of: (a) providing a stowable and deployable support structure towhich an energy-directing surface is attachable, said support structurehaving a multi-sided foldable hoop having a plurality of foldablejoints, and generally radial struts that extend from and are foldableabout corner joints of said multi-sided hoop, wherein at least one ofsaid struts is formed as a telescoping tube member and at least onedrive mechanism coupled to foldable joints of said multi-sided hoop, andbeing operative to unfold and deploy said multi-sided foldable hoop andsaid plurality of generally radial telescoping struts, and thereby saidenergy-directing surface from a folded, stowed configuration to anunfolded, deployed configuration; (b) providing a tensioning cord trussattachment framework for attaching an unfurlable energy-directingsurface to said support structure provided in step (a); (c)incorporating said energy-directing surface with said tensioning cordtruss attachment framework provided in step (b) to form a compositeenergy-directing surface assembly; and (d) attaching said compositesurface assembly formed in step (c) to said stowable and deployablesupport structure provided in step (a).
 37. A method according to claim36, wherein step (d) comprises attaching said composite surface assemblyto selected ones of said generally radial struts of said stowable anddeployable support structure.
 38. A method according to claim 36,wherein step (b) comprises forming individual cord truss elements of anupper cord truss assembly as generally planar shaped structures, andwherein step (c) comprises assembling said generally planar shapedstructures into a two-dimensional network containing a tensioned, meshfabric of which said energy-directing surface is formed, and adjustingsaid two-dimensional network to which said tensioned, mesh fabric ofwhich said energy-directing surface has been assembled, so as to conformwith a prescribed geometry specification.
 39. A method according toclaim 38, wherein step (d) further comprises adjusting attachment pointsbetween said composite antenna surface assembly and said stowable anddeployable support structure.